This invention relates to a dragline bucket and a method of operating a dragline bucket and, more particularly, to a bucket and method which avoids the problem of slewing by a novel tooth arrangement.
Dragline buckets are a species of excavating buckets which are filled by being dragged over the material or bank to be excavated by means of a dragline and then hoisted by means of a hoisting rope and thereafter dumped. Even as early as 1913, these dragline buckets were well known, see U.S. Pat. No. 1,050,838. A more recent detailed description can be seen in my U.S. Pat. No. 4,791,738.
Over all these years, buckets have slewed, i.e., shifted sideways, when encountering an off center load. This is most pronounced when keying such as cutting along a vertical sidewall or when encountering an off center boulder. I have solved this problem by arranging the teeth in a rearwardly extending V orientation, viz., the teeth project successively forward in proceeding from the longitudinal center line of the bucket toward the sidewalls thereof.
Over the long history of dragline buckets, this arrangement has not been used. The excavator of U.S. Pat. No. 2,060,867 had a reverse V configuration of teeth extending from the rear wall but performed no hoisting and dumping operation. Russian Patent 326,298 also had a reverse V configuration in a dredge but again did not perform the hoisting and dumping functions.
Although reverse V configurations of teeth art known, these have always been employed in buckets whose movement is controlled by dipper sticks or wheels and hence are not subject to slewing. Representative of this type of bucket are U.S. Pat. Nos. 3,791,054, 4,037,337 and Russian Patents 306,228 and 682,605.
A semblance of a forward V configuration is seen in a dragline bucket in U.S. Pat. No. 1,868,246. Other forward V configurations can be seen in U.S. Pat. Nos. 1,803,654, 2,629,945 and 2,660,323 but these, again, are all controlled against slewing by virtue of being rigidly mounted.
According to the invention, I arrange the teeth in a reverse V configuration on the lip of the bucket and advantageously at an angle of about 75.degree. to about 80.degree., viz., the line connecting a given point on one tooth and a corresponding point on the adjacent tooth forming an angle of about 75.degree. to about 80.degree. to the longitudinal center line of the bucket. Further, I prefer to have the lip generally planar so that the teeth operate in the same plane. With this arrangement, slewing is substantially minimized by virtue of the tooth arrangement directing the obstacle-providing material toward the center of the bucket.
The invention is further described in conjunction with an illustrative embodiment in the accompanying drawing in which
FIG. 1 is a fragmentary somewhat schematic view of a conventional dragline bucket and associated prime move showing various features of operation;
FIG. 2 is a fragmentary top plan view of the apparatus of FIG. 1 showing a conventional bucket keying against a substantially vertical sidewall or bank;
FIG. 3 is a perspective view of a bucket lip featuring the inventive tooth arrangement;
FIG. 4 is a fragmentary top plan view, partially in section, of the forward portion of a bucket utilizing teachings of this invention;
FIG. 5 is a fragmentary side elevational view, partially in section of the bucket of FIG. 4; and
FIG. 6 is a fragmentary schematic top plan view showing the practice of the invention when the bucket encounters a boulder or the like.